Dust removal camera

ABSTRACT

A dust removal camera which has an image pickup sensor which converts an optical image into an electric signal, a shutter which opens/closes an optical path to the image pickup sensor, an optical plate provided between the image pickup sensor and the shutter, and rectangularly formed, and a piezoelectric body provided to extend along an end portion of a surface of the optical plate, and to vibrate the optical plate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/210,948, filed on Aug. 24, 2005, which is a continuation of U.S.patent application Ser. No. 10/037,353, filed on Dec. 21, 2001, now U.S.Pat. No. 7,006,138, which claims the benefit of priority from JapanesePatent Application No. 2000-401291, filed Dec. 28, 2000, which areincorporated by reference as if fully set forth.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a camera with an image pickup device,and in particular to a camera where dust adhering to an interior of thecamera can be removed.

2. Description of the Related Art

Conventionally, a relatively large pixel pitch has been applied to animage pickup device. In recent years, however, in a case that a smallsized image pickup device with one million or more pixels is used in acamera, there occurs a problem that the pixel pitch becomes fine and ashadow of dust adhering to an optical element face in the vicinity of animage pickup face of the image pickup device is picked up by the imagepickup device so that the image quality of the obtained photograph isconsiderably affected by the shadow, which results in deterioration ofimage quality.

As one of methods for solving the problem, such a structure is employedthat an image pickup device section is sealed as closely as possible, oras another of the methods, such a procedure is employed that in asingle-lens reflex camera of a lens exchangeable type, a lens isdetached from a main body of the camera, and an image pickup devicesection is exposed using a special operation mode so that dust adheringto the image pickup device section is blown out by a blower or the like.

In the former method, however, in a case of a camera having a mechanismwith a mechanical focal-plane shutter, the shutter itself must be closedtightly or sealed and a sealing structure therefore is much complicated,which results in large size. Also, even when the outside of the shutteris sealed, there occurs a problem that a surface of the shutter is worndue to sliding operation of a plane of the mechanical shutter togenerate dust, and the generated dust adheres to the image pickup devicesection. Also, in a case of a shutter constituted so as to control theimage pickup device electrically instead of the mechanical shutter,there is a drawback that a time required for driving the image pickupdevice is prolonged due to a shutter control, which causes increase intemperature of the image pickup device so that the image quality of aphotograph obtained by the camera or a life of a battery cell in thecamera is reduced.

Furthermore, in the another method, such a complicated operation isrequired that an exchange lens is detached for blowing dust, or theimage pickup device is exposed in a special mode. Also, when themechanical shutter is used, the shutter must be put in an opened stateduring removal of dust. At this case, when the shutter is closedunexpectedly due to voltage shortage or the like, a blower for cleaningand the shutter plane are brought into contact with each other so thatthe shutter may be damaged.

BRIEF SUMMARY OF THE INVENTION

In view of the above circumstances, an object of the present inventionis to provide a camera having a dustproof mechanism for an image pickupdevice which is effective against dust generated after assembling thecamera, where the dustproof mechanism can be made simple and small-sizedby constituting a sealed portion of an image pickup device section in asmall size.

According to an aspect of the present invention, there is provided adust removal camera having an image pickup sensor which converts anoptical image into an electric signal; a shutter which opens/closes anoptical path to the image pickup sensor; an optical plate providedbetween the image pickup sensor and the shutter, and rectangularlyformed; and a piezoelectric body provided to extend along an end portionof a surface of the optical plate, and to vibrate the optical plate.

According to another aspect of the invention, there is provided a dustremoval camera having an image pickup optical system which picks up anoptical image of an object; an image pickup sensor which converts theoptical image into an electric signal; a shutter which opens/closes anoptical path to the image pickup sensor; an optical plate providedbetween the image pickup sensor and the shutter, and rectangularlyformed; and a piezoelectric body provided to extend along an end portionof a surface of the optical plate, and to vibrate the optical plate.

According to still another aspect of the invention, there is provided adust removal method. The method includes applying a periodic voltage toa piezoelectric body provided to extend along an end portion of asurface of an optical plate which is substantially rectangular, andwhich is located in front of an image pickup element; and causingvibration to be created at the surface of the optical plate by applyingthe periodic voltage of the piezoelectric body.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 is a sectional view of a camera according to a first embodimentof the present invention;

FIG. 2A is a perspective view of a dustproof device section according tothe first embodiment and FIG. 2B is a pattern diagram of an electricterminal for ground of the dustproof device section shown in FIG. 2A;

FIG. 3A is a circuit diagram for applying a signal to a dustproof deviceaccording to the first embodiment;

FIG. 3B is a diagram of a glass plate and a piezoelectric member of thedustproof device viewed from a direction of arrow A in FIG. 3A, and FIG.3C is a diagram showing bending vibrations of the glass plate shown inFIG. 3B;

FIG. 4 is a diagram showing an anti-static constitution of a transparentelectrode according to the first embodiment of the present invention;

FIGS. 5A to 5I are diagrams showing behaviors of dust adhering to asurface of a vibrating glass plate according to the first embodiment ofthe present invention;

FIG. 6 is a diagram showing a dustproof device section according to asecond embodiment of the present invention;

FIG. 7 is a diagram of a progressive wave according to the secondembodiment of the present invention; and

FIG. 8 is a diagram showing a dustproof device section according to thesecond embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be explained below withreference to the drawings.

FIG. 1 is a sectional view of a camera showing a first embodiment of thepresent invention, where only a main portion of the camera is shown. Atype of a camera used herein is a single-eye reflex type camera of alens exchange type, which comprises a lens assembly 1 and a camera body10. The lens assembly 1 and the camera body 10 are coupled to eachother, for example by a coupling mechanism such as a bayonet or thelike. Also, the lens system 1 has an image formation lens system 2, andan image formation position can be adjusted by moving the entire of theimage formation lens system 2 or one or some lenses constituting theimage formation lens system 2 in a direction of an optical axis. Thelens assembly 1 is also provided with a focus adjusting mechanism (notshown).

In FIG. 1, also, light rays of an object image passing through the imageformation lens system 2 are turned upwardly by a mirror 11 and anoptical image of the object image is formed on a screen 12. The opticalimage can be observed via a roof prism from an eye piece 14.

On the other hand, an image pickup face of a CCD (Charge Coupled Device)15 serving as an image pickup device in the camera according to theembodiment, which is a photoelectric transfer device, is arranged at aposition optically equivalent to the image formation face of the screen12. The CCD 15 is held in a holder 151 which is a holding member suchthat the image pickup face faces an opening portion 151 a of the holder151, and a support portion (not shown) of the holder 151 is fixed to thecamera body 10. Also, a mask 152 having a rectangular opening isprovided in front of the CCD 15 and it defines a light receiving rangeof a light receiving face of the CCD 15. Furthermore, a filter H 153which is an optical low pass filter for a reference direction, a filterV 154 which is an optical low pass filter for a direction perpendicularto the reference direction, and a filter R 155 which is an infrared rayinsulating filter are respectively provided in front of the CCD 15.

In a conventional camera, the above-mentioned structure is employed,where a front face of the filter R 155 is exposed to a space on the sideof a shutter 16. Accordingly, dust which has invaded into an inside ofthe body 10 or has been generated in the inside adheres to an exposedface of the filter R 155, and the shadow of the adhered dust is notblurred sufficiently because the exposed face and the image formationface of the CCD 15, so that the shadow is recorded as an image projectedon the image pickup face.

In this embodiment, a glass plate 17 which is an optical device is fixedto the holder 151 via a supporting body 18 so as to cover the openingportion 151 a, and the filter R 155 is sealed or closed tightly bysealing a space between the glass plate 17 and the supporting body witha visco-elastic filler. This is because, by using the visco-elasticfiller, vibrations of the glass plate 17 can be prevented from beingtransmitted to another member and vibrations of the glass plate 17itself are not obstructed. In this manner, since the glass plate 17 isarranged so as to cover the opening portion 151 a of the holder 151, aspace between the CCD 15 and the glass plate 17 is sealed by the holder151 and the glass plate 17 so that dust is prevented from invading intothe space from the outside. Accordingly, by assembling these members ina state where dust is removed from these members, the face of the glassplate 17 positioned on the side of the filter R 155 is prevented frombeing adhered with dust. Then, piezoelectric bodies a 171 and b 172 arefixed to upper and lower portions of a back face of the glass plate 17to constitute a dustproof device 170.

Next, FIG. 2A is a perspective view of a dustproof device section, andFIG. 2B shows a pattern of an electric terminal 173 for ground of thepiezoelectric bodies provided to the glass plate 17 in a fixing manner.An image formation light ray passing-through area 17 a through which alight bundle from the image formation lens system 2 passes is formed atalmost a central portion of the glass plate 17. The light bundle fromthe image formation lens system 2 passes through the image formationlight ray passing-through area 17 a to be incident on the CCD 15. Also,supporting bodies a 181 and b 181 made of material such as rubber havinga vibration absorbing characteristic are fixed to left and rightportions of the glass plate 17. Each supporting body is provided with ajoining portion recessed towards the side of the glass plate 17 by onestep size, left and right portion of the front face of the holder 151are received in the joining portion, and the holder 151 and thesupporting body are fixed to each other at the joining face. Also, alead wire G 174 connecting to the ground is welded to the electricterminal 173. Furthermore, the piezoelectric bodies a and b arerespectively provided with a lead wire Sa 174 and a lead wire Sb 175,and they are applied with a cyclic voltage. Also, the electric terminal173 may be formed by adhering an electric conductive thin film to theglass plate 17 or it may be formed by performing such a vapor depositionas a sputtering process or an electroless plating on the glass plate 17.

Next, FIG. 3A shows a schematic circuit diagram for applying a signal toa dustproof device. As shown in FIG. 3A, the piezoelectric body a andthe piezoelectric body b are polarized to the same orientation in thedirection of the thickness of the piezoelectric body (a direction of theoptical axis of the image formation lens 2) and cyclic voltage isapplied to faces of the surface sides of the piezoelectric bodies. Sucha cyclic signal may be a rectangular wave or a sine wave.

Next, FIG. 3B is a view of a state of the dustproof device obtained whena cyclic signal is applied to the dustproof device, which is viewed fromarrow A in FIG. 3A. As shown in FIG. 3B, a solid line shows a case wherea voltage is not applied to the dustproof device, a chain on the lowerside shows a case where the piezoelectric bodies are stretched byapplying + (plus) voltage to the piezoelectric bodies, and a chain lineon the upper side shows a case where the piezoelectric bodies are shrunkby applying − (minus) voltage to the piezoelectric bodies.

Next, FIG. 3C shows a bending vibrations occurring at a face of theglass plate 17 of the dustproof device which is vibrating as shown inFIG. 3B, which is positioned on the side of the shutter 16. The arrowshows a locus a mass point on a surface of the glass plate 17. The masspoint on an antinode of the bending vibration is vibrated up and down,and it has a maximum amplitude. Also, the amplitude of the mass point iszero at a position of a node of the bending vibration where the masspoint acts only a rotational motion. Between the antinode and a node ofthe bending vibration, the mass point and a portion positioned from themass point close to the node vibrate about the node in an arc shape.

Next, FIGS. 5A to 5I show the behaviors of a dust according to a timesequence in a state that the dust adheres to a surface of a glass platebefore a surface of the glass plate vibrates. FIGS. 5A to 5I show a casethat, in addition to the vibration of the glass plate, such a force asgravity acts on the dust in the direction of the plate thickness of theglass plate.

First, FIG. 5A shows a state that a dust adheres to a surface of a glassplate before the surface vibrates. In a state shown in FIG. 5B, thesurface starts to vibrate and a force shown with an arrow is appliedfrom the surface to the dust. In a state shown in FIG. 5C, the forceacting on the dust becomes weak but a force shown with an arrow isapplied on the dust. In a state shown in FIG. 5D, a vibration directionis reversed from the state shown in FIG. 5C, and when an inertial forceacting on the dust from the surface exceeds an adhering force of thedust to the surface and the gravity, the dust separates from the surfaceto continue inertial movement between the state shown in FIG. 5C and thestate shown in FIG. 5D. Then, broken lines shown in FIGS. 5D to 5F showmovement loci of the dust when a downward force (gravity, electrostaticforce or the like) in these figures is applied to the dust. Then, asshown in FIG. 5F, the dust is consequently moved leftward from the stateshown in FIG. 5A.

The reason why the dust is moved in this manner is that the vibration ofthe mass point shown in FIG. 3C has a horizontal component. Also, in thecourse from a state shown in FIG. 5H to 5I, the dust is applied with aforce from the surface, again.

In this manner, FIGS. 5A to 5I show movement of a piece of dust duringone cycle of the vibration, but when the vibration is further continued,dust gathers together at the node of vibration shown in FIG. 3C. Also,even when dust adheres to the position of the antinode of vibration,since it will be impossible that the dust is formed in a complete sphereand its center of gravity is positioned at the antinode of vibrationaccurately, when the dust separates from the surface and it adheres tothe surface again, the dust deviates from the position of the antinodeso that it is finally moved to the node of vibration. Accordingly, whenbending vibration is generated such that a node of vibration ispositioned so as to be deviated from the image formation light raypassing-through area, dust can be removed from the image formation lightray passing-through area. Also, in the present invention, such aconstitution is employed that respective nodes of vibration aresupported by the supporting body a and the supporting body b. With sucha constitution, since each node is supported at a position havingamplitude of zero, an effective supporting method can be provided whichdoes not prevent bending vibration. Further, the bending vibration canproduce a large amplitude at a signal of the lowest voltage whenresonance occurs. The resonance frequency at this time is determinedaccording to the shape and the material quality of the dustproof device,a supporting method, and a vibration mode.

Now, assuming that the dustproof device has a simple rectangular plate,the length of the long side of the plate is l, the plate thickness is h,the longitudinal elastic coefficient of the plate is E, the density ofthe plate is ρ, and a primary bending vibration as shown in FIG. 3C isproduced through a free support serving as the support, the resonancefrequency f is:$f = {\frac{1.133\pi}{\iota^{2}}\sqrt{\frac{E\quad h^{2}}{12\rho}}}$

In FIGS. 5A to 5I, the gravity is applied to the face in a verticaldirection to the face, but when the gravity is applied in an in-planedirection, dust moves in a direction of the node of the bendingvibration and it also moves in a direction of the gravity, so that it isremoved from the image formation light ray passing-through area.

Thus, in this embodiment, a voltage is applied at a frequency at whichthe glass plate 17 which is the dustproof device is resonated.

By producing a primary bending vibration in the glass plate 17 which isthe dustproof device in the above manner, dust adhering to a surface ofthe glass plate 17 can be removed from the surface. However, in a casethat a surface of the glass plate 17 is charged with static electricity,dust which has adhered on the surface of the glass plate 17 is attractedon the surface of the glass plate 17 by static electricity. Accordingly,when an attracting force is much strong, dust on the surface of theglass plate 17 may not be removed therefrom. In order to solve thisproblem, as shown in FIG. 4, a transparent electrode 41 and an electricterminal 44 conductive to the transparent electrode 41 are formed on thesurface of the glass plate 17, and the transparent electrode 41 isgrounded through the electric terminal 44 so that the glass plate 17 canbe prevented from being charged. Then, the piezoelectric bodies 42, 43are constituted on a surface of the glass plate 17 which is positionedon the side of the CCD 15, as shown in FIG. 3A, and such a vibration asmentioned above is applied to the glass plate 17, so that dust adheringon the surface of the glass plate 17 can be removed from the surface.

As mentioned above, by providing an anti-static means for preventing thesurface of the glass plate 17 from being charged, more effective dustremoving effect can be achieved. Also, besides such a constitution thatthe surface of the glass plate 17 is grounded for preventing thecharging, an effect similar to the case of grounding can be achieved byapplying an anti-static coating on the surface of the glass plate 17.

Next, FIG. 6 shows a second embodiment of the present invention. Asshown in FIG. 6, a dustproof device generating a progressive wave on aglass plate 27 is constitute by fixing piezoelectric bodies a1 271, a2272, b1 273 and b2 274 on the glass plate 27 and providing an electricterminal for grounding between each piezoelectric body and the glassplate. Each piezoelectric body has sections (expressed by symbols + and−) with different polarization directions which are arranged alternatelyin a horizontal direction. Assuming that horizontal polarizationarrangements of the piezoelectric body a1 271 and the piezoelectric bodyb1 273 are the same, and a section length of the + section and − sectionis defined as λ, the remaining piezoelectric bodies a2 272 and b2 274are arranged such that they are shifted from the arrangement positionsof the two piezoelectric bodies a1 and b1 by λ/4 in a horizontaldirection.

Cyclic voltages having the same phase are applied to the piezoelectricbodies a1 and b1 from an oscillator, respectively, while cyclic voltageswhose phases have been shifted by 90° through a 90° phase shifter areapplied to the piezoelectric bodies a2 272 and b2 274 from theoscillator. With such a configuration, as shown in FIG. 7, a progressivewave with a wavelength λ is generated on the surface of the glass plate27. FIG. 7 is a diagram of the surface of the glass plate 27 shown inFIG. 6, which is observed when the surface is viewed from a direction ofarrow B, where a one-dotted line denotes the shape of the surface justafter a voltage is applied and a double-dotted line denotes an aspectwhere a bending vibration wave progresses in a horizontal and rightwarddirection according to a time lapse.

As mentioned above, when a progressive wave occurs on the glass plate,an oval vibration (including a circular motion) in a counterclockwisedirection occurs at any mass point, as shown in FIG. 7. Since there is aleftward and horizontal component in the oval vibration, all dustadhering to a surface of the glass plate are conveyed to the left sideof the glass plate.

In the second embodiment of the present invention, since dust iscollected to one side of the glass plate, disposition of the collecteddust can be made more simply than that in the first embodiment. Also,since the amplitude of the oval vibration is the same at any portion ofthe glass plate, a force for removing dust becomes uniform over theentire surface of the glass plate. Also, in a case of the secondembodiment, the amplitude of a progressive wave can be made large byresonating the bending vibration, so that an inertial force for removingdust can be increased. Furthermore, as compared with the firstembodiment, the second embodiment of the invention has a merit that,since a vibration having a wavelength of about ⅓ the wavelength of thefirst embodiment is used, it exceeds a audible range so that operationalsound such as noise is not heard. Also, as another embodiment, such aconstitution can be employed that a progressive wave shown in FIG. 6 isnot produced in a direction of the longitudinal side of the rectangularglass plate but it is produced in a direction of the short side thereof.In this case, since the length to be vibrated is shorter than that inthe case that the progressive wave is produced in the direction of thelongitudinal side, a further short wavelength can be employed. Also, asstill another embodiment, such a constitution can be employed that aprogressive wave is produced in an orthogonal direction of therectangular glass plate and dust is collected at a corner of the glassplate, so that collection or recovery of the dust can be made easy.

Next, FIG. 8 is a perspective view of a dustproof device of a thirdembodiment of the present invention. A supporting body 38 formed of arubber having a vibration damping property or the like is fixed to aglass plate 37 and a front face of a holder 151 (not shown) is bonded toa holder butting face 381 in a butting manner therewith. A laminatedpiezoelectric body a 371 and a laminated piezoelectric body b 372 arefixed to the glass plate 37 outside the supporting body 38, and therespective laminated piezoelectric bodies are fixed with a weight a 373and a weight b 374 made of material having a relatively large specificgravity, such as, for example, tungsten, copper, or iron.

Cyclic voltage is applied to each laminated piezoelectric body from anoscillator and each of the weights a 373 and a 374 is vibrated in adirection of an optical axis of a lens. The glass plate 37 can bevibrated in the direction of the optical axis by reaction force of theweight. Dust on the surface of the glass plate can be released from thesurface by the vibration of the glass plate, so that, when vibration isapplied to the glass plate in an in-plane direction in which the gravityacts, dust is removed in a direction in which the gravity acts. Also,such a constitution can be employed that an air flow is producedsimultaneously with application of the vibration instead of the gravityso that dust is removed by action of the air flow. Any vibration whichcan achieve a similar effect can be employed in this invention.

In the dustproof device of the third embodiment, the dustproof device ofthe first embodiment can be formed by attaching a laminatedpiezoelectric body or a dustproof device in the vicinity of the antinodeof the bending vibration of the first embodiment and oscillating theoscillator at a resonance frequency. In this case, as the position wherethe laminated piezoelectric body is attached, any position other thanthe position of a node of the bending vibration can be selected.However, a bending vibration can be produced more effectively byattaching the laminated piezoelectric body in the vicinity of theantinode. Similarly, even in a case that laminated piezoelectric bodieswith a weight are fixed to positions which are shifted each λ/4 in ahorizontal direction and a phase is shifted by 90° in a time manner,when a cyclic voltage of a resonance frequency of the above-mentionedbending vibration (a bending vibration of 1.5 wavelength in a standingwave) is applied, the bending progressive wave shown in FIG. 7 occurs inthe glass plate.

Even in the second and third embodiments thus configured, anti-staticmeans such as explained in the first embodiment is provided, so that aneffect for removing dust can be enhanced.

Further, the following aspects can be considered.

Addition of Various Aspects

1. According to a first aspect of the present invention, there isprovided a camera comprising: an image pickup optical system for formingan optical image of an object a photoelectric converting device forconverting the optical image to an electric signal; a holding memberwhich holds the photoelectric transfer device and has an opening portionwhich guides lights from the image pickup optical system to thephotoelectric transfer device; an optical device which covers theopening portion and seals the photoelectric transfer device; and avibration generating device which vibrates the optical device, whereinthe optical device is attached to the holding member in the vicinity ofa node of vibration produced by the vibration generating means.

2. According to a second aspect of the invention, there is a provided acamera according to the first aspect, where the optical device is alow-pass filter.

3. According to a third aspect of the invention, there is provided acamera according to the first aspect, wherein the optical device is aninfrared isolating filter.

4. According to a fourth aspect of the invention, there is provided acamera according to the first aspect, further comprising a lightpermeable electrode formed on a surface of the optical device opposed tothe photoelectric converting device; and grounding means which iselectrically connected to the electrode to prevent the surface of theoptical device from being charged.

5. According to a fifth aspect of the invention, there is provided acamera according to the first aspect, wherein the optical device has arectangular shape, and opposed sides of one of two sets are fixed to theholding member while adhesive with elasticity is filled in a spacebetween opposed sides of the other and the holding member.

6. According to a sixth aspect of the invention, there is a cameraaccording to the first aspect, wherein the node of vibration ispositioned outside an effective permeable range of the light permeableelectrode.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A dust removal camera comprising: an image pickup sensor whichconverts an optical image into an electric signal; a shutter whichopens/closes an optical path to the image pickup sensor; an opticalplate provided between the image pickup sensor and the shutter, andrectangularly formed; and a piezoelectric body provided to extend alongan end portion of a surface of the optical plate, and to vibrate theoptical plate.
 2. The dust removal camera according to claim 1, whereinthe piezoelectric body is located opposite to the image pickup sensor.3. The dust removal camera according to claim 1, wherein the opticalplate is an infrared cutoff filter.
 4. The dust removal camera accordingto claim 1, wherein the optical plate is a low pass filter.
 5. The dustremoval camera according to claim 1, which further comprises a filterprovided between the optical plate and the image pickup sensor, andwherein a gap between the optical plate and the filter is sealed.
 6. Thedust removal camera according to claim 1, wherein the optical plate isgrounded.
 7. The dust removal camera according to claim 6, which furthercomprises a transparent electrode formed on the optical plate, andwherein the optical plate is grounded through the transparent electrode.8. The dust removal camera according to claim 1, wherein the opticalplate is subjected to an anti-static processing.
 9. The dust removalcamera according to claim 1, which further comprises anotherpiezoelectric body provided to extend along another end portion of thesurface of the optical plate.
 10. The dust removal camera according toclaim 9, wherein the end portions of the surface of the optical platealong which the piezoelectric bodies respectively extend are parallel toeach other.
 11. A dust removal camera comprising: an image pickupoptical system which picks up an optical image of an object; an imagepickup sensor which converts the optical image into an electric signal;a shutter which opens/closes an optical path to the image pickup sensor;an optical plate provided between the image pickup sensor and theshutter, and rectangularly formed; and a piezoelectric body provided toextend along an end portion of a surface of the optical plate, and tovibrate the optical plate.
 12. The dust removal camera according toclaim 11, wherein the piezoelectric body is located opposite to theimage pickup sensor.
 13. The dust removal camera according to claim 11,wherein the optical plate is an infrared cutoff filter.
 14. The dustremoval camera according to claim 11, wherein the optical plate is a lowpass filter.
 15. The dust removal camera according to claim 11, whichfurther comprises a filter provided between the optical plate and theimage pickup sensor, and wherein a gap between the optical plate and thefilter is sealed.
 16. The dust removal camera according to claim 11,wherein the optical plate is grounded.
 17. The dust removal cameraaccording to claim 16, which further comprises a transparent electrodeformed on the optical plate, and wherein the optical plate is groundedthrough the transparent electrode.
 18. The dust removal camera accordingto claim 11, wherein the optical plate is subjected to an anti-staticprocessing.
 19. The dust removal camera according to claim 11, whichfurther comprises another piezoelectric body provided to extend alonganother end portion of the surface of the optical plate.
 20. The dustremoval camera according to claim 19, wherein the end portions of thesurface of the optical plate along which the piezoelectric bodiesrespectively extend are parallel to each other.
 21. A dust removalmethod comprising: applying a periodic voltage to a piezoelectric bodyprovided to extend along an end portion of a surface of an optical platewhich is substantially rectangular, and which is located in front of animage pickup element; and causing vibration to be created at the surfaceof the optical plate by applying the periodic voltage of thepiezoelectric body.
 22. The dust removal method according to claim 21,which further comprises: applying the periodic voltage to each of thepiezoelectric body provided to extend along the end portion of thesurface of the optical plate and another piezoelectric body provided toextend along another end portion of the surface of the optical plate;and causing vibration to be created at a surface of the optical plate byapplying the periodic voltage to the piezoelectric bodies.
 23. The dustremoval method according to claim 22, wherein the end portions of thesurface of the optical plate along which the piezoelectric bodiesrespectively extend are parallel to each other, and a periodic voltageis applied to each of the piezoelectric bodies to vibrate the surface ofthe optical plate.